Project Summary The goal of this project is to introduce a new microcatheter that will significantly improve an interventional radiologist?s ability to navigate across small blood vessels. Microcatheters are designed to reach small vascular targets from access points such as the femoral or radial arteries, located up to 150 cm away. Interventional radiologists use these devices to treat a wide variety of ailments, from a traumatic vessel rupture to a hepatoma. Access and navigation of small vessels, however, can be difficult in up to 45 % of all cases, where there is challenging anatomy or when multiple targets are present. Difficulties in navigation can result in added procedure time, unpredictable scheduling, increased radiation exposure, and, in time-critical processes such as a ruptured pseudoaneurysm, poorer clinical outcomes. In cases where navigation is challenging, the interventionalist can switch to microcatheters, guidewires, or guide catheters with different shapes or stiffness to help with vessel selection, but at additional cost and time. We have developed a microcatheter, the A1, using a novel coaxial design that allows active deflection of the microcatheter tip, while satisfying the size requirements for general microvascular and neurovascular procedures and preserving the tracking and torqueing properties of existing microcatheters. This would greatly enhance the operator?s ability to navigate the vasculature, and reduce the need to stock and use passive devices with different shapes. We have provided proof of concept on a model testbed and also in vivo. In Phase 1 of this proposal we will focus on refinement our microcatheter prototypes to achieve a design freeze. This requires the development of an anatomically-accurate vascular testbed that highlights the challenges encountered by the interventional radiologist and quantitative comparisons to commercially-available microcatheters devices that will define the performance milestones of the A1 microcatheter. In Phase 2 we will focus on in vitro design verification and in vivo design validation testing versus predicate devices for a 510k application. We intend to achieve 510k clearance within 2 years and first in-human use immediately afterwards.